nvim/lua/plugins/lsp/ui.lua

local M = {}

function M.setup()
	-- Signs
	local signs = { Error = '', Warn = '', Hint = '', Info = '' }
	for type, icon in pairs(signs) do
		local hl = 'DiagnosticSign' .. type
		vim.fn.sign_define(hl, { text = icon, texthl = hl, numhl = hl })
	end

	-- Floating window borders
	local border = {
		{ '╭', 'FloatBorder' },
		{ '─', 'FloatBorder' },
		{ '╮', 'FloatBorder' },
		{ '│', 'FloatBorder' },
		{ '╯', 'FloatBorder' },
		{ '─', 'FloatBorder' },
		{ '╰', 'FloatBorder' },
		{ '│', 'FloatBorder' },
	}
	local orig_util_open_floating_preview = vim.lsp.util.open_floating_preview
	function vim.lsp.util.open_floating_preview(contents, syntax, opts, ...)
		opts = opts or {}
		opts.border = opts.border or border
		return orig_util_open_floating_preview(contents, syntax, opts, ...)
	end
end

function M.on_attach(client, bufnr)
	-- Highlight references
	if client.server_capabilities.documentHighlightProvider then
		vim.api.nvim_create_augroup('lsp_document_highlight', {
			clear = false,
		})
		vim.api.nvim_clear_autocmds {
			group = 'lsp_document_highlight',
			buffer = bufnr,
		}
		vim.api.nvim_create_autocmd({ 'CursorHold', 'CursorHoldI' }, {
			group = 'lsp_document_highlight',
			buffer = bufnr,
			callback = vim.lsp.buf.document_highlight,
		})
		vim.api.nvim_create_autocmd('CursorMoved', {
			group = 'lsp_document_highlight',
			buffer = bufnr,
			callback = vim.lsp.buf.clear_references,
		})
	end
end

return M